New Facing Targets Sputtering System
Overview | Features | Principle | Applications | Product Information
The Principles and Properties of Conventional Facing Targets Sputtering (CFTS) and New Facing Targets Sputtering (NFTS)
CFTS Structure | CFTS/CMS Differences | CFTS Issues | NFTS Improvements | NFTS Plasma Source
Technical Issues of CFTS
While CFTS technology has some superior properties relative to CMS, it also has some serious issues. Especially, anti symmetrical plasma confinement and the complexity of the equipment structure are serious issues in the case of large sized targets for wide area coating. The anti symmetrical plasma confinement results from the unequal distribution of magnetic fields symmetrically formed between rectangular facing targets. In the case where small square or circular targets are used, sputtering plasma is symmetrically generated between them, since the magnetic field is symmetrically distributed around outside of the target surfaces. However, in the case where large rectangle targets are used, magnetic fields distribute anti symmetrically around the rectangular target surfaces. This is because the edge corners and center of the targets are different in magnetic field distribution. Since the magnetic field distribution near targets surfaces correspond to sputtering plasma density, it brings about anti symmetrical sputtering plasma distribution for target erosion and sputtering rate. The sputtering plasma of CMS is confined in the space between the substrate surface and the target surface and the sputtering plasma of CFTS is confined in the space between the facing targets.
As previously explained, CFTS has the facing targets structure and the target holders are installed in a vacuum chamber. Therefore a large scale vacuum chamber is required for the equipment for wide area coating. Additionally, cooling water and electric power to the targets are provided from outside of the vacuum chamber to inside via a vacuum feedthrough. These things result in complex equipment structure and difficult maintenance.
From the above reasons, we have developed New FTS (NFTS) technology that can solve these CFTS technical issues. As a consequence of both a principal and some technical improvements, we have realized NFTS technology with high reliability and cost effective equipment for wide area coating.